Malicious PDF — malware analysis report

Static analysis result for SHA-256 5c8652356e3aa702…

MALICIOUS

PDF

63.8 KB Created: 2021-02-28 03:37:49 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-22
MD5: 83ef4ea35f485721f146f2951781b73b SHA-1: 374b47a9a81623566ab76ca3e3469cb146099371 SHA-256: 5c8652356e3aa702b17001b1454f39ca499726822e09baea489c4c24a8306da4
206 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a large number of external links, many hosted on disposable domains, indicative of a link farm. Heuristics like 'PDF_SEO_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggest this malicious intent. ClamAV detection and ML classification further confirm its malicious nature, likely serving as a lure or a distribution point for other malware.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • Callback phishing phone lure medium SE_CALLBACK_LURE
    Document asks the user to call a phone number in billing, refund, subscription, fraud, or security context — consistent with callback phishing or tech-support scam patterns. Suppressed for legitimate-issuer (IRS/gov/official-form) documents that carry no urgency or charge/dispute escalation.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://golowaki.ru/wix?keyword=building+vocabulary+skills+answers PDF link annotation
    • http://myfirstsite.xyz/fibepokejufinuvolyn5rg.pdfIn PDF document text
    • https://titugujogimob.weebly.com/uploads/1/3/4/0/134017720/70e5e435a.pdfIn PDF document text
    • https://cdn.sqhk.co/nenakowi/hc0UhiO/stick_fight_classic.pdfIn PDF document text
    • http://bio-ita.fun/felsefe_tarihi_macit_gkberk5xt5l.pdfIn PDF document text
    • http://collegegraduatecentraldating.com/tumumasakulewapidy7af.pdfIn PDF document text
    • https://cdn.sqhk.co/rorajakura/fQu8ixe/12272240348.pdfIn PDF document text
    • https://tenasedoba.weebly.com/uploads/1/3/4/3/134333827/bezinowogivos-vowuzif-gavesil-vewuwo.pdfIn PDF document text
    • https://cdn.sqhk.co/mopewedote/dgehb0B/clan_race_apk_mod.pdfIn PDF document text
    • https://zavowije.weebly.com/uploads/1/3/2/6/132680855/696224c.pdfIn PDF document text
    • https://cdn.sqhk.co/dodipenameki/hjjcigZ/penalty_kicks_game_download.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://merojupamen.epizy.com/smack_that_tamil_remix.pdfIn PDF document text
    • https://s3.amazonaws.com/tutasujal/netball_logo_templates_free.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000bd2d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBD2D 5616 bytes
SHA-256: 14d3ed1e49b0207d6e7f776816d572626836f55c9293bb9017a274ad529ebfbc
font_01_sfnt_off0000d07c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD07C 10032 bytes
SHA-256: ee4697f76e76a4087d7019359bbfc3055ecfe05b36064b310868f03b45678606

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